1. Field of the Invention
This invention relates in general to electronic devices and in particular to alignment structures for electronics racks.
2. Description of the Related Art
Electronic devices such as computer systems can be mounted in an electronics rack to save floor space. An electronics rack can house an number of electronic devices made by different electronics manufactures. Consequently, the height, width, and depth of the electronic devices housed in the rack may conform to specific standards such as the Electronics Industry Association (EIA) RS-310 19" rack standard so as to enable the devices to be mounted in an electronics rack conforming to the standard.
Electronics racks conforming to a standard have definable vertical mounting unit increments. An example of a definable mounting unit increment is a retma (U) unit for an electronics rack conforming to the EIA standard. The height of electronic devices conforming to the standard is typically sized in mounting unit increments to allow for the efficient utilization of rack space and the standardization of rack structures.
Because electronics racks conforming to EIA standards are designed to house electronic devices of various heights, vertical rack structures of an electronics rack may include mounting holes that run along the entire vertical rack structure enabling horizontal rack structures to be mounted at positions corresponding to retma unit increments. During the assembly of a rack, alignment of a horizontal structure to a particular position corresponding to a mounting unit increment can be difficult due to the large number of holes of the vertical structure.
Referring to FIG. 1, to aid in alignment of a horizontal rail (or other rack structure) during assembly, alignment structures have been added to mounting brackets to aid in their alignment on a vertical rack structure. Mounting bracket 151 includes two pin-like alignment structures 153 attached to back plate 155. Each alignment structure 153 engages a hole of the vertical rail so as to align the bracket at positions corresponding to whole mounting unit increments.
It is sometimes desirable to have electronic devices sized at increments of 1/2 mounting unit increments to more efficiently utilize rack space. However, sizing equipment by 1/2 mounting unit increments requires that horizontal rack structures be mounted at positions corresponding to 1/2 mounting unit increments. The present inventor has determined that what is desirable is a mounting bracket that is alignable at positions on a vertical rack member corresponding to both whole mounting unit increments and at 1/2 mounting unit increments.